Parallels between spacing effects during behavioral and cellular learning

Abstract

Repeated learning improves memory. Temporally distributed (“spaced”) learning can be twice as efficient than massed learning. Importantly, learning success is a non-monotonic maximum function of the spacing interval between learning units. Further optimal spacing intervals seem to exist at different time scales from seconds to days. We briefly review the current state of knowledge about this “spacing effect” and then discuss very similar but so far little noticed spacing patterns during a form of synaptic plasticity at the cellular level, called long term potentiation (LTP). The optimization of learning is highly relevant for all of us. It may be realized easily with appropriate spacing. In our view, the generality of the spacing effect points to basic mechanisms worth for coordinated research on the different levels of complexity.

How odor cues help to optimize learning during sleep in a real life-setting

“…However, continuous stimulation with auditory cues can be problematic because of a certain refractoriness pattern: Auditory stimulus presentation needs to be below a certain temporal duration 33 and spaced in time within the SWS stage in order to prevent the disappearance of the beneficial effect of cueing. The latter strongly reminds of well-known spacing effects 15,[34][35][36] or retroactive interference effects during learning 16 . Our continuous odor stimulation during night shows that the refractoriness problem is at least not that severe in the olfactory domain.…”

“…Given that all of these factors (except the first) could have introduced additional "experimental noise" into our data, it is remarkable that our effect sizes with Cohen's d between 0.6 and 1.2 are in the same range as, or larger than the effect size (d ≈ 0.6) in Rasch et al 's study 15 (we have estimated this value from the leftmost graph of their Fig. 2A).…”

Memory Takes Time

“…On the other hand, with no spacing at all the stimuli simply combine additively into a single stimulus of increased amplitude. “Massed” stimuli, however, do not generally produce the same effects as spaced stimuli, a difference that is consistently observed on multiple time scales of behavioral learning and its cellular analogs (Kornmeier and Sosic-Vasic, 2012; Smolen et al, 2016). Thus, neuronal learning depends on the specific temporal relationships between the time windows of first messenger availability.…”

Role of calcium, glutamate and NMDA in major depression and therapeutic application

“…Glutamate is the primary excitatory neurotransmitter in the brain (Kornmeier and Sosic-Vasic, 2012). Glutamate is found in substantially higher concentrations than monoamines and in more than 80% of neurons, cementing its role as a major excitatory synaptic neurotransmitter.…”